Patent DE-102006038631-A1 (DE)
Title: Preparation of ethyl cyclohexane comprises hydrogenation of ethyl cyclohexane contaminated with ethylbenzene, in a precious metal catalyst that is suspended in the liquid phase
Inventor: MUELLER PETER
IPC: C07C7/163
Filed: 2006-08-17
Abstract: Preparing ethyl cyclohexane (ECH) comprises providing ECH contaminated with ethyl benzene, adding a catalyst, replacing the inertization medium by hydrogen, circulating the mixture, heating the reactor and terminating the phase, filling the reactor with partial technical ECH, circulating the content and terminating the cycle, replacing the partial quantity of hydrogenation product by technical ECH, circulating the content and terminating the reaction, maintaining the temperature at 60-130[deg] C and pressure at 5-20 bars, supplying hydrogen, agitating the mixture and terminating the reaction. Preparation of ethyl cyclohexane by hydrogenation of 4-vinyl cyclohexene or ethyl cyclohexane (ECH) (technical ethyl cyclohexane) that is contaminated with ethyl benzene, in a precious metal catalyst that is suspended in the liquid phase, where the reaction is carried out in several reaction cycles in a loop reactor, comprises (a) at the start-up phase, providing a first partial quantity of ECH (contaminated ECH) as an initial product, adding a catalyst, replacing the inertized and the inertization medium by hydrogen, forcing the reaction mixture to circulate, heating the reactor to a reaction temperature and terminating the start-up phase, if the uptake of hydrogen drops to a specified threshold value; (b) at the beginning of the subsequent first reaction cycle, filling the reactor with the second partial quantity of the initial product such as either technical ECH or 4-vinyl-cyclohexene, forcing the reactor contents to circulate and terminating the reaction cycle, if the uptake of hydrogen drops to a specified threshold value, where immediately after the termination of the reaction cycle, a predetermined partial quantity of the hydrogenation product is led out of the reaction cycle; (c) during all the other reaction cycles, replacing the partial quantity of hydrogenation product that is led out of the reaction cycle after the previous reaction cycle by technical ECH or 4-vinyl cyclohexene, forcing the reactor contents to circulate and terminating the respective reaction cycle after reaching the threshold value for the uptake of hydrogen; and during each of the reaction cycles, maintaining the reaction temperature at 60-130[deg] C and a pressure of 5-20 bars, supplying hydrogen by means of a dispersion device that is mounted in the loop reactor, agitating the reaction mixture with a turbulent flow, monitoring the reactivity of the catalyst and terminating the reaction in the case of strongly decreasing reactivity of the catalyst. An independent claim is included for a device for implementing the above procedure comprising a loop reactor, in whose pipeline system for circulatory flow (11), a heatable reactor (1), a circulating pump (12), a heat exchanger (13), a metal candle filter (14) for the discharge of hydrogenated product, a feed mechanism for initial product and a jet pump (9) are connected, where the jet pump is mounted at the head of the reactor, protrudes into the reactor and is connected with a pipeline (8) for the supply of hydrogen, where the pipeline is connected with a pipeline (10) for the reflux of non-consumed hydrogen from the reactor, and in the reactor, pipeline (4) for feeding a liquid catalyst and a pipeline (5) for feeding an inertization agent are mounted.